A pressure ulcer, as defined by the National Pressure Ulcer Advisory Panel (NPUAP), is "any lesion caused by unrelieved pressure resulting in damage of underlying tissue. Pressure ulcers are usually located over bony prominences (such as the sacrum, coccyx, hips, heels) and are staged according to the extent of observable tissue damage. Pressure ulcers vary from superficial tissue damage to deep craters exposing muscle and bone."1
As alluded to in this definition, a staging system is used to provide clinical communication about the anatomic depth of a pressure ulcer. In the United States, the most commonly used system of staging these chronic wounds is the NPUAP's staging system,1 which grew out of the NPUAP's 1989 consensus conference.2 It has been amended over the years to refine the definition of a Stage I pressure ulcer3 (Table 1). The NPUAP staging system builds on the work of Shea4 and the International Association of Enterostomal Therapists5 (now known as the Wound, Ostomy and Continence Nurses Society), and it was adopted in 1994 by the panel developing the Agency for Health Care Policy and Research's pressure ulcer treatment clinical practice guideline.6
The NPUAP staging system is not without problems. Since 1989, it has been used erroneously to document healing or lack of healing, denote quality of care indicators, and identify negligent care. It could certainly be argued that these uses (or misuses) severely stress the original intention of the staging system.
In addition, clinicians are often confused by the differences in the stages and the intent of the system. Even experienced clinicians may lack agreement in labeling pressure ulcers by stage.7 Clinicians have incorrectly used the NPUAP pressure ulcer staging system to stage wounds with etiologies other than pressure, including nonhealing surgical wounds, venous ulcers, diabetic foot wounds, and arterial ulcers. This has complicated the language of the staging system, made application of the system fuzzy, and reduced researchers' ability to fully understand the extent of the problem of pressure ulcers.
WHAT IS A DEEP TISSUE INJURY?
Another factor complicating the pressure ulcer picture is a type of lesion that an NPUAP task force has dubbed "deep tissue injury."8 These lesions are likely due to ischemia of the muscle bed and occlusion of the vertical perforating blood vessels feeding the skin through the muscle. They cannot be staged according to the NPUAP's current staging system,1 although they were likely identified as "closed pressure ulcers" in Shea's staging system.4
To address these unique and potentially dangerous lesions, the NPUAP convened a Deep Tissue Injury Task Force in 2001. The task force developed a working definition of deep tissue injury: "A pressure-related injury to subcutaneous tissues under intact skin. Initially, these lesions have the appearance of a deep bruise, and they may herald the development of subsequent development of a Stage III-IV pressure ulcer even with optimal treatment."8
Because deep tissue injury has not been given a staging label, it has been difficult to track. A review of the literature used to label deep tissue injury identified the variations in terminology describing these lesions.8 The lack of consistent labeling has prohibited formal study of the incidence, prevalence, and etiology of deep tissue injury.
DEVELOPMENT OF A CONSENSUS CONFERENCE
Once the task force identified the issues surrounding deep tissue injury, the NPUAP began planning a consensus conference at which the definition of deep tissue injury, as well as possible revisions of the Stage I and Stage II pressure ulcer definitions, would be discussed and debated among wound care practitioners. A consensus conference has been defined as a means for gaining public support for difficult decisions in science and technology.9 As mentioned earlier, NPUAP began using the consensus conference format in 1989 when the Stage I through Stage IV pressure ulcers definitions were debated.2
The 2005 consensus conference had 3 goals:
- to discuss how the addition of deep tissue injury to the nomenclature of pressure ulcers would affect clinical practice
- to discuss how the incorporation of deep tissue injury into the pressure ulcer nomenclature would affect the definition of Stage I pressure ulcers
- to discuss whether the definition of Stage II pressure ulcers should be redefined to include or exclude the broad array of dermal injuries in the current definition.
The first step in the consensus conference process was the development of white papers on Stage I pressure ulcers, Stage II pressure ulcers, and deep tissue injury. These white papers were posted on the NPUAP Web site and comment was invited. One of the more comprehensive responses was formulated by the Wound, Ostomy and Continence Nurses Society.10
The consensus conference was held in February 2005. Attendees from a variety of disciplines assisted in making the discussion robust and providing a 360-degree look at the issues. These attendees included nurses; certified wound, ostomy, and continence nurses; nurse practitioners; physicians; scientists; physical therapists; nutritionists; and policymakers. In addition, several members of NPUAP's European counterpart, the European Pressure Ulcer Advisory Panel, were present.
At the conference, didactic presentations on labeling, natural history, and histology of deep tissue injury and Stage I and II pressure ulcers were provided. Ample time was allowed for discussion of the didactic material.
DISCUSSION AND QUESTIONS
To fully explore all aspects of the issues, breakout groups were organized, with random assignment of attendees to each group. All groups discussed the same questions. Opinions were written by a scribe, both at the computer and on paper. The set of initial responses was then discussed by the entire group. At the end of the discussion, the ideas were summarized and collapsed into like ideas for voting.
The participants discussed 3 questions:
- How would the addition of deep tissue injury to the nomenclature of pressure ulcers affect clinical practice?
- The discussion of this question centered on 5 themes: (1) education will be needed on the new type of pressure ulcer; (2)practice will change because these wounds will require more frequent assessment and aggressive intervention; (3)regulation will change because these new wounds will need to be identified, documented, and investigated; (4) litigation will change due to the increased understanding of the timing of onset and pattern of deterioration; and (5) research is needed on methods to diagnose deep tissue injury.
- The various groups offered 23 different statements in response to this question, and a vote was taken to determine which statements the participants agreed with most (Table 2). The greatest level of agreement was found with the idea that the inclusion of deep tissue injury into the staging language would help guide more aggressive, early, appropriate interventions that may lead to better outcomes. The second area of group consensus was that deep tissue injury has a questionable knowledge base, a complex pathogenesis, and a need for reliable and valid clinical indicators and definitions to improve outcomes and clarify statistical reports of prevalence and incidence.
- How would the incorporation of deep tissue injury into the pressure ulcer nomenclature affect the definition of Stage I pressure ulcers?
- For the second question, discussion centered on 3 areas: (1) revising the Stage I definition, including use of fewer labels (erythema, blanchable), use of a specific time frame in which these wounds exist, and designation of these wounds as early tissue injury; (2) eliminating the term Stage I pressure ulcer and instead calling it a closed pressure ulcer or an unstageable pressure ulcer; and (3) eliminating the entire staging system and referring to pressure ulcers as partial-thickness ulcers and full-thickness ulcers, with an indication that the wound was caused by pressure.
- Attendees reached consensus by vote on the concept of eliminating the entire staging system and replacing it with partial-thickness and full-thickness labels and clinical descriptions (Table 3). The group also agreed that the addition of deep tissue injury would create a need to change the entire staging system, and that a Stage I label should be used as a designation for early (minor) tissue injury.
- The Stage II definition is used to describe a variety of dermal injuries. Should Stage II be redefined to include or exclude this broad array of dermal injuries?
- Top responses focused on the idea that the Stage II definition is confusing because it includes both pressure and non-pressure-induced skin breakdown. Attendees agreed that all non-pressure-induced dermal injuries should be excluded from the Stage II definition (Table 4). They also said that the term Stage II should be eliminated and replaced with the term partial-thickness wound and a description of its specific etiology. In addition, attendees were vocal about the need to develop a user-friendly definition for this stage.
Throughout the conference, it became apparent that the group was in complete consensus about 4 important issues. No formal ballot was cast, but the attendees orally agreed that they held consensus on these items:
- Pressure can cause injury to soft tissues. Throughout the conference, there was ongoing discussion on whether a Stage II pressure ulcer is a real entity. Attendees felt that all partial-thickness ulcers develop from other etiologies, such as friction and maceration, which strip epidermal layers. Although no experimental studies have been conducted on the development of Stage II or partial-thickness pressure ulcers from pressure alone, the entire group agreed that ulceration could develop from pressure-induced displacement of capillary blood flow in the skin.
- Deep tissue injury due to pressure exists as a form of pressure ulcer and is not well captured by current staging. Deep tissue injury was validated as a form and etiology of pressure ulcer. Although little formal study has been done on this type of pressure ulcer, the group agreed that it does exist.
The proper language to stage deep tissue injury remained controversial. The group felt that deep tissue injury could be called a variant of Stage I using the current terminology. Stage I pressure ulcers have classically been accepted as ulcers that can heal on their own without regeneration of significant tissues or production of scar. Deep tissue injury may not fit well into this category, except to indicate that in its closed presentation, deep tissue injury often heralds the development of more severe ulcers.
Staging deep tissue injury as an unstageable pressure ulcer was also recommended. The NPUAP has recommended that deep tissue injury be documented in the unstageable category in those health systems where staging wounds is mandatory (such as with computerized documentation) because the true extent of the wound is not known. When a health care system uses narrative documentation, objective description was recommended, along with the label of deep tissue injury.
The more traditional use of the label unstageable is for wounds covered with slough or eschar, in which the true depth of the wound is obscured until debridement. It is not expected that all deep tissue injuries will require debridement. Further, collapsing deep tissue injury into an unstageable category may prolong the ability to fully understand the phenomenon.
- Current staging definitions of Stage I and Stage II are not working. Attendees were in complete consensus that the current definitions of Stage I and Stage II pressure ulcers allowed too many variations. Although an absolute decision on what the new terminology should be was not reached, attendees did not dispute that excoriation from urine and feces, maceration from moisture, and friction injury do not describe pressure ulcers of the epidermis and dermis.
- The etiology of any wound is critical to include in the label for the wound in order to prescribe treatments. Although the NPUAP's staging system was designed only for pressure ulcers, the Stage II definition is encumbered by other wound etiologies and pressure relief alone would not improve those wounds. The use of skin protectants and antifriction devices are important components of these managing these other ulcers.
The consensus process is an effective method of reaching a common understanding of complex issues. The NPUAP's 2005 consensus conference validated the presence of deep tissue injury as a form of pressure ulcer, as well as the problems with the current definitions of Stage I and Stage II pressure ulcers. The NPUAP will consider these recommendations in its future work.
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9. National Institutes of Health. Guidelines for the Planning and Management of NIH Consensus Development Conferences. Bethesda, MD: National Institutes of Health; 2004.
10. Wound, Ostomy and Continence Nurses Society. A response to the NPUAP. Available at: http://www.wocn.org/pdf/npuap.pdf
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